Найти корни уравнений 1) 11x^2 - 6x - 27 = 8x^2 - 6x; 2) 26 + 5y - 0,5y^2 = 2,5y^2 + 26; 3) - 7x^2 + 13x + 9 = - 19 + 13x; 4) 21z + 11 = 11 + 17z - 5z^2

1) 11x^2 - 6x - 27 = 8x^2 - 6x;

11x^2 - 6x - 27 - 8x^2 + 6x=0

3x^2-27=0

3x^2=27

x^2=9

x=±3

2) 26 + 5y - 0,5y^2 = 2,5y^2 + 26

- 0,5y^2 + 5y + 26 - 2,5y^2 - 26 = 0

-3y^2 + 5y = 0

y (-3y+5) = 0

y=0 или - 3y+5=0

-3y=-5

y=5/3

3) - 7x^2 + 13x + 9 = - 19 + 13x

-7x^2 + 13x + 9 + 19 - 13x = 0

-7x^2 + 28 = 0

-7x^2=-28

x^2=-28 / (-7)

x^2=4

x=±2

4) 21z + 11 = 11 + 17z - 5z^2

21z + 11 - 11 - 17z + 5z^2=0

5z^2 + 4z=0

z (5z+4) = 0

z=0 или 5z+4=0

5z=-4

z=-0,8